Highly stretchable and customizable microneedle electrode arrays for intramuscular electromyography

Area of Science:

• Bioelectronic interfaces
• Neuroscience
• Tissue engineering

Background:

• Stretchable three-dimensional (3D) penetrating microelectrode arrays offer potential for minimally invasive sensing and stimulation in dynamic tissues.
• Fabricating custom stretchable 3D microelectrode arrays faces challenges in material integration and patterning.

Purpose of the Study:

• To present the design, fabrication, and application of stretchable microneedle electrode arrays (SMNEAs).
• To enable sensing of local intramuscular electromyography (EMG) signals ex vivo using SMNEAs.

Main Methods:

• A hybrid fabrication scheme combining laser micromachining, microfabrication, and transfer printing was employed.
• The fabrication process allows for scalable production of individually addressable SMNEAs with high device stretchability (60-90%).
• Electrode geometries, recording regions, impedance, array layout, and length distribution are customizable.

Main Results:

• Individually addressable SMNEAs with high stretchability were successfully fabricated.
• The SMNEAs demonstrated customizable electrode properties.
• SMNEAs were utilized as bioelectronic interfaces to record intramuscular EMG signals from various muscle groups in *Aplysia*.

Conclusions:

• SMNEAs represent a versatile platform for minimally invasive bioelectronic sensing.
• The developed fabrication method facilitates the creation of custom, high-performance stretchable microelectrode arrays.
• This technology holds promise for applications in neuroscience, tissue engineering, and wearable bioelectronics.